clapp



M.' R. GLAPP. STEAM BOILER.

No. 28,711. PatentedJune 12, 1860.

UNrTED srnrns iiunnr onirica.

M. R. OLAPP, OF SENECA FALLS, NEIV YORK, vASSIGNOR TO SILSBY, MYVNDERKSE & CO., OF SAME PLAGE.

STEAM-BOILER.

Specification of Letters Patent No. 28,711, dated June 12, 1860.

To all 'whom t may concern:

Be it known that I, M. R. CLAPP, of Seneca Falls, in the county of Seneca and State, of New York, have invented a new and useful Improvement in Steam-Boilers; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification, in whichy Figure 1 is a vertical section of an uprightboiler with my improvement. Fig. 2 is a horizontal section of the same, in the plane indicated by the line of Fig. 1.

Similar letters of reference indicate corresponding parts in both figures.

My invention consists in a certain arrangement of water tubes in twos, one within another, within the fire box of a boiler, with the lower ends of both extending below the grate, and their upper ends even or nearly so with the crown of the fire box and below the surface of the water, whereby a very rapid generation of steam is obtained accompanied by a very free natural circulation of water to supply the place of what is converted into steam.

To enable others skilled in the art tov make and use my invention, I will proceed to describe its construction and operation.

A, C, is the outershell of the boiler.

B, B, are the sides of the fire box, and D, a tube sheetforming the crown thereof.

E, E, are smoke tubes leading from the fire box through the upper tube sheet C, to the chimney which is to be arranged above the said sheet.

The water is intended to fill the space between A and B, B, and to cover the tube sheet D, to a sufficient depth for perfect safety. The grate is intended to rest on an annular plate or ange E, surrounding the bottom of the interior of the re box.

F, F, and G, Gr, are the water tubes which constitute the subject of my invention and which may be arranged vertically or inclined, as represented. The outer tubes F, F, have screw threads cut in the exterior of each end, and are inserted upwardly through holes provided for them in the annular plate or flange E, to receive the caps H, H, which are screwed on the exteriors. The inner tubes Gr, G, which are considerably smaller t-han the outer ones F, F, may be made of very light metal, and have their lower ends slit and spread open as shown at a, a, in Fig. 1. They are dropped loosely into the outer tubes F, F, before the latter are inserted, and are of such length that while their lower ends rest on the caps H, H, their upper ends are even or nearly so with the upper ends of the outer tubes, and with the tube sheet D, so that water may flow freely into them from above the said tube sheet, and also circulate between them and the outer tubes F, F.

The boiler having been filled with water to the required height above the tube sheet D, and fire made on the grate, steam is generated rapidly between the tubes F, F, and those G, G, by the heat acting on the outer surface of the former, and as the said steam rises between the said tubes, and an upward circulation of water is there produced, a downward circulation is produced in the inner tubes where there is not heat enough to make steam in any considerable quantity, and the water so circulating downward passes through the slits a, a, of the latter tubes to keep up a constant supply to the space between them and the outer tubes F, F. In this way a constant circulation of wat-er is kept up, not only in Contact with the tubes F, F, but in contact with the tube sheet D, and provision is made for a very rapid generation of steam. The constant circulation of water through the tubes keeps those tubes Gr, Gr, in their proper place in the tubes F, F, the former adapting themselves to the circulation by always inclining themselves toward those sides of F, F, where the circulation is weakest and less space is required. This arrangement of tubes possesses the following advantages over other arrangements of tubes in twos, one within another: 1st, the outer tubes being screwed into the crown sheet and passing down to the bottom of the boiler, or below the grate can be taken out for clean ing or repair. 2nd, by extending the tubes below the fire a better circulation is insured than when their bottoms are exposed to the fire. 3rd, by inserting the inner tubes loosely within the outer ones, the cost of fitting the tubes is greatly reduced, and they can easily ends below the lire and both their upper encls below the water level substantially as here specified.

M. R. CLAPP. Witnesses:

GEO. O. DAVIDs, M. L. BELLoWs. 

